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I (No ModeL) v F, G. DURANT &' D. EDWARD. I FLOAT FO RSTEAM.APPARATUSAND OTHER PURPOSES.

o. 259,833. [Paten ed June20,"18-8 2 1!. PETERS. PholoLithog pMr. wuunmn, DvC.

UNITED STATES PATENT OFFICE.

FREDERICK O. DURANT AND DAVID EDWARD, OF NEW YORK, N..Y.

FLOAT FOR STEAM APPARATUS AND OTHER PURPOSES.

SPECIFICATION forming 'part of Letters Patent No. 259,833, dated June20, 1882. I Application filed December 23, 1881. (No model) To all whomit may concern:

Be it known that we, FREDERICK O. DU- RANT and DAVID EDWARD, bothcitizens of the United States, residing at- New York, in the county andState of New York, have invented new and useful Improvements in Floatsfor Steam Apparatus and other- Purposes, of

which the following is a specification.

This invention consists in a float composed of two hemispherical shells,one of which is provided with a male and the other with a femalescrew-thread, by means of which the same are united.

This invention is illustrated in the accompanying drawings,in whichFigure 1 represents a side elevation of thejhalf-shell with the femalescrew-thread. Fig. 2 is asimilar view of the half-shell with the malescrewthread. Fig. 3 is a central section of the float when complete.

Similar letters indicate corresponding parts.

The usual method of constructing floats for steam apparatusis asfollows: Two hemispherical shells are produced of sheet-copper, eitherby spinning or by striking them up, and these half-shells are thenconnected by brazing or by flanging them together. These operationsrequire great skill and much time, and, even with the utmost care, it isextremely clifficult to render the float thus produced perfectly tight,since the seams, even if they are tight at the beginning, are liable toopen when the floats are exposed to a variable pressure and temperature.These disadvantages are overcome by our invention.

We construct our float of two half-shells, A B, which are by preferencecast of brass or other suitable metal. The half-shellA is then providedwith a female screw-thread, a, and, the half-shell B with a malescrew-thread, b, and for this purpose the last-named half-shell isprovided with an internal rim, 0, on the outer surface of which thescrew-thread b is out. The operation of cutting these screwthreads canbe effected in a comparatively short time, and when the two half-shellsaie united, as shown in Fig. 3, thatportion of the float where the seamis formed is strengthened by the internal rim, 0, to such an extent thatthe seam cannot possibly be opened by the external pressure to which thefloat may be exposed, the seam being the last portion which will giveway it the pressure rises beyond the desired limit, and at the same timethe outer surface of the float remains smooth and uniform throughout.For the purpose of uniting the two half-shells we cast on each a seriesof lugs or projections, 01 (I, so that by applyinga suitable wrench thetwo half-shells can be screwed together as firmly as may be required.

In order to render the joint perfectly tight, a small quantity of redlead or other equivalent material is applied to the threads (I 1) beforescrewing them together. After the two halfshells have been screwedtogether the outside surface may be turned off, so as to reduce theweight of the float as much as may be desirable. I

By these means we are enabled to produce floats of great strength atmuch less expense than that of the ordinary sheet-metal floats.

What we claim as new, and desire to secure by Letters Patent, is-- Afloat having a uniformly-smooth outer sur- V face, and composed of twohalf-shells, which are united by a male and female screw-thread,

one of said half-shells being provided with an Witnesses:

J AS. W. HALE, r EDWIN L. CARPENTER.

